Usual metastatic localizations in MTC are liver, bone and lung. We report two cases with metastases in pancreas and breast.

In a 51-year-old woman were discovered several nodules in the thyroid gland: 29×19 mm in the right lobe and 5 mm in the left. Calcitonine (CT) levels were 2300 and ECA 44 ng/ml. Fine-needle aspiration of the main nodule confirmed MTC. Total thyroidectomy and right jugulo carotidal lymph node dissection were performed in 1998 with pretracheal and recurrent dissection. Pathological examination confirmed that the main nodule was a non-encapsulated MTC with two additional micro-MTC. Several lymph nodes were invaded. CT, ECA and CgA ab+. A RET mutation in codon 620 was found. Post surgical CT was never normal: CT rising from 40 (until 2003) to 80 (2005), 90 (2006), 150 (2007), 270 (2008) and 490 (2009). Calcium, PTH and methoxyamine levels were normal. Search for metastases was negative (repeated cervical and liver US with contrast, FDG PET-scan (2005) and F-DOPA (2007), cervical and lung CT scan) but in 2009 MRI discovered a 13 mm lesion of the pancreatic uncus. It was enucleated (CT 93) and the pathologist confirmed 18×13 mm metastasis (CT, synaptophysine and CgA+; Ki67 35%) with invasion of 2/5 lymph nodes.

In a 52-year-old woman, the increasing size of a nodule in the right thyroid lobe with elevated CEA necessitated total thyroidectomy with right jugulo carotidal and latero-tracheal lymph node dissection in 1990. MTC with lymph nodes invasion (7/11) was found. A new surgery was performed by sternotomy with additional lymph node invasion (2/23). The patient was not cured (calcitonin 845→3760 ng/ml in 1994). No RET mutation. A third surgery with recurrent dissection found 5/13 lymph nodes invaded. CT level was 840 ng/ml post surgery and increased to 1285 (1995), 2670 (1997), 6000 (2001), 7500 (2006), 9850 (2009). Repeated imaging was normal (cervical and liver US, CT scan, anti-CEA immuno-scintigraphy, FDG PET-scan, MRI) and radioimmuno-therapy in 1997 was unsuccessful. In 2009, bone scintigraphy found several localizations and X-ray of the breast discovered a 8 mm right mass. It was found a MTC breast metastasis (CT and CgA+; Ki67 <3%) (three lymph nodes +). Post surgical CT 6100 increased to 8400. In summary, two unusual MTC metastases localizations (pancreas 11 years after discovery; breast 19 years later).